We've waited for months and months, with speculation and conspiracy theories flying about, but no more.

Finally Samsung have revealed what it was that caused many copies of the Galaxy Note 7 phablet to explode.

They released their findings as promised yesterday. According to the company’s own investigation and independent scientific analysis of the issues by three consulting bodies, the overheating was caused by separate problems in batteries sourced from two different suppliers.

Their report stated that the batteries sourced from Samsung SDI didn't have enough room between the heat-sealed protective pouch around the battery and its internals. Because the phone was so slim, tight quarters placed stress on the upper right corner of each battery. In the worst scenarios, that caused electrodes inside each battery to crimp and come into contact, leading to thermal runaway and short circuiting.

Focusing on the batteries sourced from Amperex Technology Limited, some cells were missing insulation tape, and some batteries had sharp protrusions inside the cell that led to damage to the separator between the anode and cathode. The batteries also had thin separators in general, which increased the risks of separator damage and short circuiting.

The findings were announced after testing 200,000 devices and 30,000 batteries in a giant charging and recharging test facility built for the task. Samsung mobile communications chief D.J. Koh says a team of 700 company engineers conducted internal testing, and independent reviews of potential problems were carried out by UL, Exponent, and TÜV Rheinland.

At the event announcing these findings Samsung stated that it has overhauled its safety testing process as a result of the investigations.

According to Koh, “We are taking responsibility for our failure to identify the issues arising out of the battery design and manufacturing process prior to the launch of the Note 7,”

Samsung added that it explored any potential problems involving system software, manufacturing, and Note 7 hardware during its months-long investigation. They tested with the phone’s iris-scanning feature turned on and off, downloaded third-party apps to see if that had any effect, and tested to see if USB-C charging played a role.

There were a lot of new technologies with the phone seeing as it was supposed to be a game changer of sorts and with this came the possibility of danger. But is seems it didn't. According to Jay Whitacre, a Professor of Materials Science and Engineering and Engineering and Public Policy, he said of USB-C charging having a role to play in the explosion, “It seems unlikely, since the battery-facing components in most phones are chips that are used broadly in many phones,

“A cell made to be fast-charged should be engineered to accept the high currents without overheating or having internal shorts. As long as a battery is designed to be fast-charged, it should pose no additional danger.”

Whatever perfect storm of power-management failures could have occurred, they shouldn’t have caused the battery to explode. Safe lithium-ion batteries have features that mitigate disaster in these types of situations, but short circuits and internal battery damage are harder to defend against.

“A well-designed battery with good safety considerations should be able to safely fail in the event of a faulty control circuit,” Whitacre says. “It might vent or puff up, but not actually burn or flame.”

Koh has stated that Samsung will now safety-test batteries at every point in the manufacturing process. They’ll also train employees at every level of the supply chain.

It is hoped that with this there is some progress made on the size of batteries viz a viz the size of the phone and that a disaster of this scale is prevented from ever happening again.